IPTables Configuration for DDoS Protection

The following IPTables configuration will assist with traffic that the DDoS filters cannot fully mitigate.
 
Note: These are a generic ruleset and should be expanded further to suit your specific application.
 
### IP Tables DDOS Protection Rules ###

### 1: Drop invalid packets ###
/sbin/iptables -t mangle -A PREROUTING -m conntrack --ctstate INVALID -j DROP

### 2: Drop TCP packets that are new and are not SYN ###
/sbin/iptables -t mangle -A PREROUTING -p tcp ! --syn -m conntrack --ctstate NEW -j DROP

### 3: Drop SYN packets with suspicious MSS value ###
/sbin/iptables -t mangle -A PREROUTING -p tcp -m conntrack --ctstate NEW -m tcpmss ! --mss 536:65535 -j DROP

### 4: Block packets with bogus TCP flags ###
/sbin/iptables -t mangle -A PREROUTING -p tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG NONE -j DROP
/sbin/iptables -t mangle -A PREROUTING -p tcp --tcp-flags FIN,SYN FIN,SYN -j DROP
/sbin/iptables -t mangle -A PREROUTING -p tcp --tcp-flags SYN,RST SYN,RST -j DROP
/sbin/iptables -t mangle -A PREROUTING -p tcp --tcp-flags SYN,FIN SYN,FIN -j DROP
/sbin/iptables -t mangle -A PREROUTING -p tcp --tcp-flags FIN,RST FIN,RST -j DROP
/sbin/iptables -t mangle -A PREROUTING -p tcp --tcp-flags FIN,ACK FIN -j DROP
/sbin/iptables -t mangle -A PREROUTING -p tcp --tcp-flags ACK,URG URG -j DROP
/sbin/iptables -t mangle -A PREROUTING -p tcp --tcp-flags ACK,FIN FIN -j DROP
/sbin/iptables -t mangle -A PREROUTING -p tcp --tcp-flags ACK,PSH PSH -j DROP
/sbin/iptables -t mangle -A PREROUTING -p tcp --tcp-flags ALL ALL -j DROP
/sbin/iptables -t mangle -A PREROUTING -p tcp --tcp-flags ALL NONE -j DROP
/sbin/iptables -t mangle -A PREROUTING -p tcp --tcp-flags ALL FIN,PSH,URG -j DROP
/sbin/iptables -t mangle -A PREROUTING -p tcp --tcp-flags ALL SYN,FIN,PSH,URG -j DROP
/sbin/iptables -t mangle -A PREROUTING -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j DROP

### 5: Block spoofed packets ###
/sbin/iptables -t mangle -A PREROUTING -s 224.0.0.0/3 -j DROP
/sbin/iptables -t mangle -A PREROUTING -s 169.254.0.0/16 -j DROP
/sbin/iptables -t mangle -A PREROUTING -s 172.16.0.0/12 -j DROP
/sbin/iptables -t mangle -A PREROUTING -s 192.0.2.0/24 -j DROP
/sbin/iptables -t mangle -A PREROUTING -s 192.168.0.0/16 -j DROP
/sbin/iptables -t mangle -A PREROUTING -s 10.0.0.0/8 -j DROP
/sbin/iptables -t mangle -A PREROUTING -s 0.0.0.0/8 -j DROP
/sbin/iptables -t mangle -A PREROUTING -s 240.0.0.0/5 -j DROP
/sbin/iptables -t mangle -A PREROUTING -s 127.0.0.0/8 ! -i lo -j DROP

### 6: Drop ICMP/Ping (you usually don't need this protocol) ###
/sbin/iptables -t mangle -A PREROUTING -p icmp -j DROP

### 7: Drop fragments in all chains ###
/sbin/iptables -t mangle -A PREROUTING -f -j DROP

### 8: Limit connections per source IP ###
/sbin/iptables -A INPUT -p tcp -m connlimit --connlimit-above 111 -j REJECT --reject-with tcp-reset

### 9: Limit RST packets ###
/sbin/iptables -A INPUT -p tcp --tcp-flags RST RST -m limit --limit 2/s --limit-burst 2 -j ACCEPT
/sbin/iptables -A INPUT -p tcp --tcp-flags RST RST -j DROP

### 10: Limit new TCP connections per second per source IP ###
/sbin/iptables -A INPUT -p tcp -m conntrack --ctstate NEW -m limit --limit 60/s --limit-burst 20 -j ACCEPT
/sbin/iptables -A INPUT -p tcp -m conntrack --ctstate NEW -j DROP

### 11: Use SYNPROXY on all ports (disables connection limiting rule) ###
#/sbin/iptables -t raw -D PREROUTING -p tcp -m tcp --syn -j CT --notrack
#/sbin/iptables -D INPUT -p tcp -m tcp -m conntrack --ctstate INVALID,UNTRACKED -j SYNPROXY --sack-perm --timestamp --wscale 7 --mss 1460
#/sbin/iptables -D INPUT -m conntrack --ctstate INVALID -j DROP

### SSH brute-force protection ###
/sbin/iptables -A INPUT -p tcp --dport ssh -m conntrack --ctstate NEW -m recent --set
/sbin/iptables -A INPUT -p tcp --dport ssh -m conntrack --ctstate NEW -m recent --update --seconds 60 --hitcount 10 -j DROP

### Protection against port scanning ###
/sbin/iptables -N port-scanning
/sbin/iptables -A port-scanning -p tcp --tcp-flags SYN,ACK,FIN,RST RST -m limit --limit 1/s --limit-burst 2 -j RETURN
/sbin/iptables -A port-scanning -j DROP
 
  • 0 کاربر این را مفید یافتند
آیا این پاسخ به شما کمک کرد؟

مقالات مربوطه

Advanced DDoS Settings

The "DDoS Settings" menu item within the dedicated panel allows configuration of advanced DDoS...

DDoS Protection FAQ

Q. How much protection is included with each server? A. Each dedicated server includes 10 Gbps...

Recommended DDoS Settings for Minecraft Servers

The following DDoS settings are recommended for running Minecraft servers. Please remember that...

Powered by WHMCompleteSolution